1. Field of the Invention
This invention pertains to a support for a vegetation line trimmer and more particularly to a support using a fully-rotatable, spherical ball for easy movement over the supporting surface.
2. Background of the Invention
A wide variety of vegetation trimmers that utilize a rotating string or line are currently available in the marketplace. These devices are typically referred to by many names including Weed Eaters, Weed Whackers, line trimmers, string trimmers, and line-type vegetation trimmers. Hereinafter and for the purposes of this invention, they are referred to as line trimmers or trimmers.
Such trimmers are typically powered by an electric or gasoline engine. The line trimmer consists of a downward facing rotating head covered by an arcuate line shield with a down-turned flange at its radially outermost end. The head and shield are mounted at the lower end of a tubular shaft having one or more handles at or near its upper end. The power source may be located anywhere along the tubular shaft but is typically located at the end away from the trimmer head. The line trimmer is designed so that the line rotates in a generally horizontal plane about a vertical axis.
Typically the line trimmer is completely supported by the operator. That is, no part of the line trimmer is designed for contact with a supporting surface or object. Because of this lack of support, conventional line trimmers are a source of muscle strain, especially for individuals not used to a large amounts of physical activity.
To remedy this problem, several attempts have been made to provide support for the line trimmer. Shivers et al. (U.S. Pat. No. 4,873,819) has completely redesigned the grass trimmer to include a structural support frame with a single ground engaging wheel connected to the frame with the trimmer portion positioned to rotate around the wheel. Foster (U.S. Pat. No. 5,279,102) uses a large wheel requiring a handle for use in guiding the carriage when it is attached to the line trimmer. Andrew et al. (U.S. Pat. No. 5,095,687) provides a wheeled attachment that is connected to the line shield and to the shaft of the trimmer.
Wheeled devices such as those used by Andrew and Shivers et al. tend to lodge in small ruts and divets typically found in the area to be trimmed resulting in forced and jerky motions of the trimmer requiring considerable force to free them from their bound position. Also, because these devices pivot or turn on at least two different axes, they are extremely susceptible to binding as a result of vegetation cuttings becoming entangled in the pivoting mechanisms by which the wheel turns and rotates. Foster attempts to alleviate this problem by providing a rather substantial wheel which, because of its size, presents its own weight and steering problems which result in the need for a separate guide handle for guiding the apparatus. All of the devices rely on the operator's skill and sense in providing a level cut. None of these devices or the line trimmers themselves provide a visual indicator as to whether the cutting line is in a horizontal cutting position. As a result, the vegetation height can vary considerably, often giving an unsightly appearance to the vegetation after it has been trimmed.